No, DAS return times are good "any time after x:xx" until park closing for the day. You just can't get another DAS return time until you use or cancel it.
FP+ times do need to be used within the hour window, though I believe there may be a slight grace period (up to 15 minutes after). I've heard the grace period was honored but also read of people turned away if they missed their window.
Thats good to know. So if we have registered a DAS time for a ride and we have a meltdown or otherwise need some 'quiet time' and don't make it back at the assigned time we will still be golden when we are ready to go again. =D That makes me happy.
no there is no end time for the DAS some times with the paper ones ( they stll give them out at attraction ) they will put an end tme you just have to tell them not too